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<pre><span class="sourceLineNo">001</span><a id="line.1">/*</a>
<span class="sourceLineNo">002</span><a id="line.2"> * Licensed to the Apache Software Foundation (ASF) under one or more</a>
<span class="sourceLineNo">003</span><a id="line.3"> * contributor license agreements.  See the NOTICE file distributed with</a>
<span class="sourceLineNo">004</span><a id="line.4"> * this work for additional information regarding copyright ownership.</a>
<span class="sourceLineNo">005</span><a id="line.5"> * The ASF licenses this file to You under the Apache License, Version 2.0</a>
<span class="sourceLineNo">006</span><a id="line.6"> * (the "License"); you may not use this file except in compliance with</a>
<span class="sourceLineNo">007</span><a id="line.7"> * the License.  You may obtain a copy of the License at</a>
<span class="sourceLineNo">008</span><a id="line.8"> *</a>
<span class="sourceLineNo">009</span><a id="line.9"> *      http://www.apache.org/licenses/LICENSE-2.0</a>
<span class="sourceLineNo">010</span><a id="line.10"> *</a>
<span class="sourceLineNo">011</span><a id="line.11"> * Unless required by applicable law or agreed to in writing, software</a>
<span class="sourceLineNo">012</span><a id="line.12"> * distributed under the License is distributed on an "AS IS" BASIS,</a>
<span class="sourceLineNo">013</span><a id="line.13"> * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.</a>
<span class="sourceLineNo">014</span><a id="line.14"> * See the License for the specific language governing permissions and</a>
<span class="sourceLineNo">015</span><a id="line.15"> * limitations under the License.</a>
<span class="sourceLineNo">016</span><a id="line.16"> */</a>
<span class="sourceLineNo">017</span><a id="line.17">package org.apache.commons.dbutils.handlers;</a>
<span class="sourceLineNo">018</span><a id="line.18"></a>
<span class="sourceLineNo">019</span><a id="line.19">import java.sql.ResultSet;</a>
<span class="sourceLineNo">020</span><a id="line.20">import java.sql.SQLException;</a>
<span class="sourceLineNo">021</span><a id="line.21"></a>
<span class="sourceLineNo">022</span><a id="line.22">import org.apache.commons.dbutils.ResultSetHandler;</a>
<span class="sourceLineNo">023</span><a id="line.23"></a>
<span class="sourceLineNo">024</span><a id="line.24">/**</a>
<span class="sourceLineNo">025</span><a id="line.25"> * {@code ResultSetHandler} implementation that converts one</a>
<span class="sourceLineNo">026</span><a id="line.26"> * {@code ResultSet} column into an Object. This class is thread safe.</a>
<span class="sourceLineNo">027</span><a id="line.27"> *</a>
<span class="sourceLineNo">028</span><a id="line.28"> * @param &lt;T&gt; The type of the scalar</a>
<span class="sourceLineNo">029</span><a id="line.29"> * @see org.apache.commons.dbutils.ResultSetHandler</a>
<span class="sourceLineNo">030</span><a id="line.30"> */</a>
<span class="sourceLineNo">031</span><a id="line.31">public class ScalarHandler&lt;T&gt; implements ResultSetHandler&lt;T&gt; {</a>
<span class="sourceLineNo">032</span><a id="line.32"></a>
<span class="sourceLineNo">033</span><a id="line.33">    /**</a>
<span class="sourceLineNo">034</span><a id="line.34">     * The column number to retrieve.</a>
<span class="sourceLineNo">035</span><a id="line.35">     */</a>
<span class="sourceLineNo">036</span><a id="line.36">    private final int columnIndex;</a>
<span class="sourceLineNo">037</span><a id="line.37"></a>
<span class="sourceLineNo">038</span><a id="line.38">    /**</a>
<span class="sourceLineNo">039</span><a id="line.39">     * The column name to retrieve.  Either columnName or columnIndex</a>
<span class="sourceLineNo">040</span><a id="line.40">     * will be used but never both.</a>
<span class="sourceLineNo">041</span><a id="line.41">     */</a>
<span class="sourceLineNo">042</span><a id="line.42">    private final String columnName;</a>
<span class="sourceLineNo">043</span><a id="line.43"></a>
<span class="sourceLineNo">044</span><a id="line.44">    /**</a>
<span class="sourceLineNo">045</span><a id="line.45">     * Creates a new instance of ScalarHandler.  The first column will</a>
<span class="sourceLineNo">046</span><a id="line.46">     * be returned from {@code handle()}.</a>
<span class="sourceLineNo">047</span><a id="line.47">     */</a>
<span class="sourceLineNo">048</span><a id="line.48">    public ScalarHandler() {</a>
<span class="sourceLineNo">049</span><a id="line.49">        this(1, null);</a>
<span class="sourceLineNo">050</span><a id="line.50">    }</a>
<span class="sourceLineNo">051</span><a id="line.51"></a>
<span class="sourceLineNo">052</span><a id="line.52">    /**</a>
<span class="sourceLineNo">053</span><a id="line.53">     * Creates a new instance of ScalarHandler.</a>
<span class="sourceLineNo">054</span><a id="line.54">     *</a>
<span class="sourceLineNo">055</span><a id="line.55">     * @param columnIndex The index of the column to retrieve from the</a>
<span class="sourceLineNo">056</span><a id="line.56">     * {@code ResultSet}.</a>
<span class="sourceLineNo">057</span><a id="line.57">     */</a>
<span class="sourceLineNo">058</span><a id="line.58">    public ScalarHandler(final int columnIndex) {</a>
<span class="sourceLineNo">059</span><a id="line.59">        this(columnIndex, null);</a>
<span class="sourceLineNo">060</span><a id="line.60">    }</a>
<span class="sourceLineNo">061</span><a id="line.61"></a>
<span class="sourceLineNo">062</span><a id="line.62">    /**</a>
<span class="sourceLineNo">063</span><a id="line.63">     * Creates a new instance of ScalarHandler.</a>
<span class="sourceLineNo">064</span><a id="line.64">     *</a>
<span class="sourceLineNo">065</span><a id="line.65">     * @param columnName The name of the column to retrieve from the</a>
<span class="sourceLineNo">066</span><a id="line.66">     * {@code ResultSet}.</a>
<span class="sourceLineNo">067</span><a id="line.67">     */</a>
<span class="sourceLineNo">068</span><a id="line.68">    public ScalarHandler(final String columnName) {</a>
<span class="sourceLineNo">069</span><a id="line.69">        this(1, columnName);</a>
<span class="sourceLineNo">070</span><a id="line.70">    }</a>
<span class="sourceLineNo">071</span><a id="line.71"></a>
<span class="sourceLineNo">072</span><a id="line.72">    /** Helper constructor</a>
<span class="sourceLineNo">073</span><a id="line.73">     * @param columnIndex The index of the column to retrieve from the</a>
<span class="sourceLineNo">074</span><a id="line.74">     * {@code ResultSet}.</a>
<span class="sourceLineNo">075</span><a id="line.75">     * @param columnName The name of the column to retrieve from the</a>
<span class="sourceLineNo">076</span><a id="line.76">     * {@code ResultSet}.</a>
<span class="sourceLineNo">077</span><a id="line.77">     */</a>
<span class="sourceLineNo">078</span><a id="line.78">    private ScalarHandler(final int columnIndex, final String columnName) {</a>
<span class="sourceLineNo">079</span><a id="line.79">        this.columnIndex = columnIndex;</a>
<span class="sourceLineNo">080</span><a id="line.80">        this.columnName = columnName;</a>
<span class="sourceLineNo">081</span><a id="line.81">    }</a>
<span class="sourceLineNo">082</span><a id="line.82"></a>
<span class="sourceLineNo">083</span><a id="line.83">    /**</a>
<span class="sourceLineNo">084</span><a id="line.84">     * Returns one {@code ResultSet} column as an object via the</a>
<span class="sourceLineNo">085</span><a id="line.85">     * {@code ResultSet.getObject()} method that performs type</a>
<span class="sourceLineNo">086</span><a id="line.86">     * conversions.</a>
<span class="sourceLineNo">087</span><a id="line.87">     * @param rs {@code ResultSet} to process.</a>
<span class="sourceLineNo">088</span><a id="line.88">     * @return The column or {@code null} if there are no rows in</a>
<span class="sourceLineNo">089</span><a id="line.89">     * the {@code ResultSet}.</a>
<span class="sourceLineNo">090</span><a id="line.90">     *</a>
<span class="sourceLineNo">091</span><a id="line.91">     * @throws SQLException if a database access error occurs</a>
<span class="sourceLineNo">092</span><a id="line.92">     * @throws ClassCastException if the class datatype does not match the column type</a>
<span class="sourceLineNo">093</span><a id="line.93">     *</a>
<span class="sourceLineNo">094</span><a id="line.94">     * @see org.apache.commons.dbutils.ResultSetHandler#handle(java.sql.ResultSet)</a>
<span class="sourceLineNo">095</span><a id="line.95">     */</a>
<span class="sourceLineNo">096</span><a id="line.96">    // We assume that the user has picked the correct type to match the column</a>
<span class="sourceLineNo">097</span><a id="line.97">    // so getObject will return the appropriate type and the cast will succeed.</a>
<span class="sourceLineNo">098</span><a id="line.98">    @SuppressWarnings("unchecked")</a>
<span class="sourceLineNo">099</span><a id="line.99">    @Override</a>
<span class="sourceLineNo">100</span><a id="line.100">    public T handle(final ResultSet rs) throws SQLException {</a>
<span class="sourceLineNo">101</span><a id="line.101"></a>
<span class="sourceLineNo">102</span><a id="line.102">        if (rs.next()) {</a>
<span class="sourceLineNo">103</span><a id="line.103">            if (this.columnName == null) {</a>
<span class="sourceLineNo">104</span><a id="line.104">                return (T) rs.getObject(this.columnIndex);</a>
<span class="sourceLineNo">105</span><a id="line.105">            }</a>
<span class="sourceLineNo">106</span><a id="line.106">            return (T) rs.getObject(this.columnName);</a>
<span class="sourceLineNo">107</span><a id="line.107">        }</a>
<span class="sourceLineNo">108</span><a id="line.108">        return null;</a>
<span class="sourceLineNo">109</span><a id="line.109">    }</a>
<span class="sourceLineNo">110</span><a id="line.110">}</a>




























































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